How do some hormones affect only certain cells in the body but not others? 1.only cells having specific receptors for a hormone can respond to the hormone's presence. 2.the hormones only go to some cells in the body but not to others. 3.special molecules on cells that are not affected break down the hormone before the cell can recognize it. 4.some cells have the wrong temperature to respond to the hormone.

Which of the following descriptions of proteins are true? i. proteins can have different sequences of amino acids. ii. proteins can have different shapes. iii. proteins can have different numbers of amino acids. a. only i and ii are true. b. only ii and iii are true. c. only i and iii are true. d. i and ii and iii are all true. e. none are true statements

Which best describes red blood cells? a. they are colorless b. they protect against disease-carrying microorganisms c. they transport oxygen throughout the body d. they aid in blood clotting

The earth consists of a variety of different organisms. despite their diversity, however, some similarities on the structural and metabolic levels may be seen. these similarities can be attributed to a. similarities among organisms in their proteins and nucleic acids. b. the ability of organisms to readily adapt to sudden environmental changes. c. similarities in organisms' habitats and niches. d. the ability of all organisms to interbreed and produce new species.